A Single-arm Phase II Study of Circulating Soluble Vascular Endothelial Growth Factor Receptor 2 (VEGFR-2) as Predictor of Benefit From Bevacizumab (Bev) Beyond Progression in Metastatic Colorectal Cancer (mCRC) - the CIRCUS Study

A growing amount of reports has consistently evidenced that a sustained inhibition of the angiogenesis is an effective therapeutic strategy, able to improve the outcome of metastatic colorectal cancer (mCRC) patients.

In the last decade different biologic agents targeting angiogenesis have been approved for the treatment of mCRC, such as bevacizumab, aflibercept and regorafenib, and, more recently, solid evidences have demonstrated the efficacy of a sustained antiangiogenic approach even beyond the first progression to a bevacizumab-containing regimen. In particular, two phase III randomized trials proved the effectiveness of prosecuting bevacizumab in second-line switching the chemotherapeutic regimen in patients already treated with bevacizumab in first-line. Preliminary experiences evidenced that circulating levels of angiogenesis-related markers are significantly modulated during first-line chemotherapy plus bevacizumab. In particular, a wide variability of plasma soluble Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) levels is observed at the time of disease progression and retrospective data suggest that benefit from the continuation of bevacizumab may be restricted to patients with high levels of soluble VEGFR-2 at the first evidence of disease progression. This study aims at prospectively validating those retrospective data.